diff --git a/ceo/excep.py b/ceo/excep.py
index 635930236..71465b7ac 100644
--- a/ceo/excep.py
+++ b/ceo/excep.py
@@ -7,6 +7,7 @@ This module provides some simple but generally useful exception classes.
 class InvalidArgument(Exception):
     """Exception class for bad argument values."""
     def __init__(self, argname, argval, explanation):
+        Exception.__init__(self)
         self.argname, self.argval, self.explanation = argname, argval, explanation
     def __str__(self):
         return 'Bad argument value "%s" for %s: %s' % (self.argval, self.argname, self.explanation)
diff --git a/ceo/members.py b/ceo/members.py
index 373dc0019..21013dc21 100644
--- a/ceo/members.py
+++ b/ceo/members.py
@@ -52,6 +52,7 @@ class MemberException(Exception):
 class InvalidTerm(MemberException):
     """Exception class for malformed terms."""
     def __init__(self, term):
+        MemberException.__init__(self)
         self.term = term
     def __str__(self):
         return "Term is invalid: %s" % self.term
@@ -59,12 +60,14 @@ class InvalidTerm(MemberException):
 class NoSuchMember(MemberException):
     """Exception class for nonexistent members."""
     def __init__(self, memberid):
+        MemberException.__init__(self)
         self.memberid = memberid
     def __str__(self):
         return "Member not found: %d" % self.memberid
 
 class ChildFailed(MemberException):
     def __init__(self, program, status, output):
+        MemberException.__init__(self)
         self.program, self.status, self.output = program, status, output
     def __str__(self):
         msg = '%s failed with status %d' % (self.program, self.status)
diff --git a/ceo/urwid/groups.py b/ceo/urwid/groups.py
index e8fa66aa2..5110bb4ee 100644
--- a/ceo/urwid/groups.py
+++ b/ceo/urwid/groups.py
@@ -1,6 +1,5 @@
 import urwid
 from ceo import members
-from ceo.excep import InvalidArgument
 from ceo.urwid import search
 from ceo.urwid.widgets import *
 from ceo.urwid.window import *
diff --git a/ceo/urwid/info.py b/ceo/urwid/info.py
index 3dab4ac78..b27a11a57 100644
--- a/ceo/urwid/info.py
+++ b/ceo/urwid/info.py
@@ -1,6 +1,4 @@
 import urwid
-from ceo import members
-from ceo.excep import InvalidArgument
 from ceo.urwid.widgets import *
 from ceo.urwid.window import *
 
diff --git a/ceo/urwid/ldapfilter.py b/ceo/urwid/ldapfilter.py
index 6aee34131..406e3d1d1 100644
--- a/ceo/urwid/ldapfilter.py
+++ b/ceo/urwid/ldapfilter.py
@@ -19,10 +19,10 @@ class LdapFilter:
             if key == 'enter' or key == 'down' or key == 'up':
                 attr = self.escape(self.attr)
                 search = self.escape(self.widget.get_edit_text(self))
-                filter = '(%s=%s)' % (attr, search)
+                ldfilter = '(%s=%s)' % (attr, search)
                 try:
                     matches = self.ldap.search_s(self.base,
-                        ldap.SCOPE_SUBTREE, filter)
+                        ldap.SCOPE_SUBTREE, ldfilter)
                     if len(matches) > 0:
                         (_, attrs) = matches[0]
                         for (k, v) in self.map.items():
diff --git a/ceo/urwid/main.py b/ceo/urwid/main.py
index a5da33ca3..b923a9fc8 100644
--- a/ceo/urwid/main.py
+++ b/ceo/urwid/main.py
@@ -1,6 +1,5 @@
 import random, ldap, urwid.curses_display
-from ceo import members, terms
-from ceo.excep import InvalidArgument
+from ceo import members
 from ceo.urwid.widgets import *
 from ceo.urwid.window import *
 from ceo.urwid import newmember, renew, info, search, positions, groups
@@ -151,5 +150,4 @@ def start():
         print "Hint: You may need to run 'kinit'"
 
 if __name__ == '__main__':
-    import os
     start()
diff --git a/ceo/urwid/newmember.py b/ceo/urwid/newmember.py
index 1a56608c2..cb42e4f22 100644
--- a/ceo/urwid/newmember.py
+++ b/ceo/urwid/newmember.py
@@ -1,6 +1,5 @@
 import urwid
 from ceo import members, terms
-from ceo.excep import InvalidArgument
 from ceo.urwid.widgets import *
 from ceo.urwid.window import *
 
diff --git a/ceo/urwid/positions.py b/ceo/urwid/positions.py
index 33d89e2b9..cb4cb880a 100644
--- a/ceo/urwid/positions.py
+++ b/ceo/urwid/positions.py
@@ -1,6 +1,5 @@
 import urwid
 from ceo import members
-from ceo.excep import InvalidArgument
 from ceo.urwid.widgets import *
 from ceo.urwid.window import *
 
diff --git a/ceo/urwid/search.py b/ceo/urwid/search.py
index fa66b522b..3fb57b708 100644
--- a/ceo/urwid/search.py
+++ b/ceo/urwid/search.py
@@ -1,6 +1,5 @@
 import urwid
 from ceo import members, terms
-from ceo.excep import InvalidArgument
 from ceo.urwid.widgets import *
 from ceo.urwid.window import *